Thermostatic control device



July 8, 1930.

LE ROY W. WILLIS 'rnzauos'm'rlc CONTROL DEVICE Filed larch 1, i929 INVENTOR zefio nf. milw,

ATTORNEY Patented July 8, 1930 UNITED STATES PATENT OFFICE LE ROY W. W ILLIS, BROOKLYN, NEW YORK, ASSIGNOR TO INTERTYPE CORPORA- TION, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK THERMOSTATIC CONTROL DEVICE Application filed March 1,

"the metal pots of commercial type casting machines and particularly to machines of this class which cast type bars or slugs, an example of a machine of this class being shown and described in U. S. Letters Patent No. 436,532 granted September 16, 1890 to O. Mergenthaler.

to regulate the supply of gas or electricity.

It has been found desirable however to provide or employ a control device which is capable of governing thesupply of gas and of electricity either concurrently or separately, whereby the control device may be applied universally to a metal pot which is heated either by a gas burner or by electrical heating means and moreover, it may be applied to a metal pot which is heated both by gas and electricity, in which instance, a single control device may be utilized to govern concurrently the supply of gas and electricity to the metal pot. I

The primary object of the present invention is to provide a'novel and improved automatic temperature control device which is capable of governing the supply of gas and electricity, either separately or simultaneously to the metal pot of the type casting machine for heating the. metal pot.

Another object of the invention is to provide a device of this character wherein the means for controlling the supply of the different forms of heat energy coact and are operative from a single thermostat.

A further object is to provide a device of this character; wherein the supply of heat from one source may be regulated and ad- 1929. Serial No. 343,648.

energy from the other source.

To these and other ends, theinvention consists in certain improvements and combinations and arrangements of parts, all as will be hereinafter more fully described, the fea tures of novelty being pointed out particularly in the claims at the end of the specification. v

In the accompanying drawings Fig. 1 is an elevation of a thermostatic control device adapted for use in connection with the metal pot of a typographical machine and embodying the present invention, the front or cover plates of the device being removed; I

Fig. 2 represents a vertical cross section taken on the line 22 of Fig. 1 and looking toward the right; 7

Fi 3 is a view similar to Fig. 1 but showing t e heat energy control devices in their "ju'sted independently of the supply of; heat I a twoextreme positions by their full and dotted lines respectively; and

Fig. 4 represents a horizontal cross section taken on the line 4-4 of Fig. 1 and looking (li)Wl1W&Idly, the cover plate being shown in p ace.

Similar arts are designated by the same reference 0 aracters in the different figures. Automatic control devices embodying the present invention are applicable to various uses where it is desirable or necessary to maintain a medium at a substantially constant rede-termined temperature by regulation 0 the supply of heat energy thereto; a1

through'the invention is more particularly applicable to the metal pots of typographical machines for the purpose of maintaining the molten metal at a substantially constant predetermined temperature in order to effect elli cient operation of the casting mechanism and especially to insure the production of type or type bars or slugs which will be free from imperfections, or substantially so. The preferred embodiment of the invention is shown 9 and such will be included within the scope of the claims.

The automatic temperature control device, as shown in the present instance, comprises generally a gas governor A and electrical control means B, these elements of the device being combined as a unit and controlled by a single or common thermostat.

The gas governor as shown is similar, in its construction and mode of operation to that disclosed in U. S. Letters Patent No. 1,210,045. granted December 26, 1916 to M. Butts, it being believed sufficient for the presen purposes to describe the gas governor as comprising a casing 1 having an interior chamber the front of which may be closed by a removable cover 2, one wall of the casing having a groove 3 therein one end of which is in communication with an inlet pipe 4 through which illuminating or other combustible gas for the gas burner of the metal pot is supplied, the side of the casing beyond the groove 3 having an outlet 5 which serves to conduct the gas admitted by the gas governor to the gas burner of the metal pot. The interior chamber of the casing 1 contains a valve 6 which-has a face which is adapted to seat against the side of the casing 1 which surrounds the groove 3 therein, one end of this valve having a lug 7 fixed to it and projecting therefrom in a direction which is at an angle to the plane of the seat engaging face of the 'valve One end of the valve is arranged to abut against the inner end of an adjustable screw 8, this screw serving to limit the movement of the valve in one direction and providing a fulcrum on which the valve may rock toward seated and unseated position with respect to the side of the casing in which the groove 3 is formed, the valve being so constructed that when it is fully seated flatwise against the portion of-the side of the casing which contains the groove 3, theadmission of gas to the interior of the casing through the inlet 4 is cut off, and when the valve is rocked more or less in a direction away from the side of thecasing containing the groove 3, gas may flow from the inlet 4 into the groove 3 and from the latter into the interior chamber of thecasin-g, and the gas thus admitted to, the chamber may flow out through the outlet 5 and thus pass to the gas burner of the metal pot, which may be of the usual or well known construction. A )ilot light screw 9 is preferably threa ed through the side of the casing in which the groove 3 is formed and this screw is adjusted so that its inner end will engage the valve 6 and thereby prevent com lete seating thereof, sd that a small flow 0 gas is allowed to pass through the governor under conditions where the automatic control means would otherwise cause complete closing of the valve and cutting ofi of the gas suply, the pilot screw thus allowing the flow ofa suflicientamount of gas to the burner to maintain a small or pilot light. The valve 6 is yieldingly urged toward its seat by a spring 10.

The thermostat for the gas governor, which also serves to govern the operation of the electric-control means, may be of different forms, 1

the thermostat shown comprising a sleeve 11 composed of a metal or material having a relatively high coeflicient of expansion, this sleeve being threaded or otherwise secured in the bottom of the casing 1 of the gas governor and being of suitable size and length to be immersed in the molten metal contained in the metal pot, and the other element of the thermostat comprises a rod 12 which is composed of a metal or material having a relatively low coefficient of expansion, the upper end of this rod abutting pivotally against the under side of the lug 7 as at 13 on the valve and the lower end of this rod abutting against a suitable seat 14 formed within the sleeve 11 near the lower end thereof. In operation, the valve 6 will be moved toward or from its seat by the differential expansion and contraction of the sleeve 11 and rod 12 which form the temperature responsive elements of the thermostat. At temperatures below the predetermined or normal operating temperatures, the sleeve 11 and the rod 12 will be relatively contracted, and since the sleeve 11 will be contracted to a greater extent than the rod 12, the rod 12 will be forced bodily upwardly by reason of its engagement with the lower end of the sleeve 11 and, in consequence, the lug 7 of the valve will be acted on in a manner which will force the upper end of the valve against the lower end of the screw 8 and to cause the valve to rock about the lower end of the screw 8 as a fulcrum, into a more or less unseated position; and when the temperature is at or above the predetermined or normal temperature at which the molten metal in the metal pot should be maintained, the sleeve 11 will be expanded to a degree which will bring the rod 12 into a bodily lowered position, in consequence of which the valve will be moved toward seated position under the influence of the spring 10. During the normal operation of the device as applied to the metal pot of a typographical machine, a drop in the temperature of the molten metal in which the sleeve 11 is immersed will cause contraction of this sleeve in consequence of which the valve 6 will be moved to a further opened position. and an increase in the temperature of the molten metal will cause expansion or lengthening of thereof by screws 16 or Other suitable means;

the temperature of the molten metal, and an approximately constant temperature of the molten metal may thus be maintained, the screw 8 being adjusted to set the governor to maintain the particular temperature desired The electric control means for automatically governing the supply of electric current to the metal pot to heat it, comprises a casing 15 which may, as shown, be'formed separately from the casing 1 of the gas governor but may be rigidly secured to a side lVithin this casing is mounted a tube 17 preferably of glass and evacuated of air, the tube being elongated in form and having electric terminals or electrodes 18 and 19 sealed or otherwise fitted into one end thereof, the tube also containing a body 2001? metallic mercury which partially fills the tube so that the terminals or electrodes 18 and 19 will not be bridged by the mercury when the tube is in its normal or substantially horizontal position. The electrodes 18 and 19 in the tube are connected by flexible wires or other suitable conductors 21 and 22 to binding posts or terminals 23 and 24 which are mounted in a suitably insulated manner upon the casing 15, it being understood that the electric' heating circuit for the metal pot is connected to these binding posts and that the closing of the electric heating circuit is controlled by the electrodes 18 and 19 and the body of mercury 20.

The tube 17 is supported, preferably removably, by a yoke-shaped clip 25 which is rotatably mounted on a pivot pin or stud 26 which is secured in fixed positionin the back of the casing 15, the yoke being removably retained on the pivot pin 26 by a slotted washer 27 which removably engages a groove in the periphery of the ivot pin 26, or a cotter pin or other suitab e means maybe employed for retaining the yoke 25 on the pin 26. This pivotal mounting of the yoke 25 and the tube 17 carried by it, on a horizontal axis, enables the tube to be rocked in a direc' tion which will raise or lower either end thereof, and when the end of the tube containing the electrodes 18 and 19 is lowered I to a sufficient degree by the rocking of the tube, the bod of mercury 20 which flows to the lower en of the tube, will cover both of the electrodes 18 and 19 as shown by the full lines in Fig. 3 and it will thereby complete an electric circuit between these electrodes, and when the tube occupies an approximately horizontal position as shown in Fig. 1 or an oppositely inclined or rocked position as indicated by the dotted lines in Fig. 3, the

i upper electrode 18 or both of the electrodes 18 and 19 will be out of contact with the body of mercury, and in either of those instances the 'circuit will not be closed through these electrodes. 3

Means is provided whereby the thermostat which controls the operation of the gas gover- 1 pivotally mounted on a pivot pin 30 gsupported in the lower portion of the casing 15, this lever being 'removably retained on its pivot pin by a slotted washer 31 similar to the washer 27, or by any other suitable means. The upper end of the lever 29 is formed with a gear segment 32 which meshes with the gear, 28 attached to the yoke 25, and the lower end of the lever 29 carries a nut 33 in which a screw or the threaded portion of a rod 34 is threaded, the nut 33 being preferably split as shown and the threaded portion of the rod 34 having a relatively tight fit therein. One end of'the rod 34 is provided with a head 35 which is preferably squared or in the form of a nut while the opposite end of the rod 34 extends through a slot 36 formed in the wall of the casing 15 and is provided exteriorly of the casing with a head or handle 37 by means of which the rod 34 may be r0- tated to adjust it axially with respect tothe nut 33. A spring 38 is connected at one end to a wall of the casing 15 and at its opposite end to a lug 39 on the lever 29, this spring acting on the lever 29 to urge it always in a direction which will maintain the face of the head 35 of the rod 34 in engagement with a plunger 40. The. plunger 40 provides the connecting or controlling link between the thermostat and the electrical control means, it extending through the walls of the casings 1 and 15 so that it may reciprocate axially therethrough and theopposite end of this plunger being operatively connected to the thermostat preferably by abutting against the free or laterally swinging end of the gas governing valve 6. Since the interior chamber of the gas governor casing 1 contains 7 gas, suitable means is provided'to prevent the'escape of such gas into the casing 15 containing the electrical controlmeans, a thin flexible metal diaphragm 41 being shown for this purpose in the present instance, the diaphragm being secured at its center to the plunger 40 and being secured at its periphery between suitable washers 42 com osed of' rubber or other suitable material, t e center of the diaphragm being sealed to the plunger and its periphery being sealed by the washers so that the. escape of gas along the plunger and into the casing 15 is prevented although w the diaphragm will not interfere with free axial movements of the plunger since the diaphragm is free to yield whenthe plunger is moved axially. The pressure of the head 35 against the plunger 40, under the influence of the spring 38, maintains the opposite end of the plunger in contact with the gas valve 6, and since the latter is connected to the thermostat by the 'enga ement of its lug 7 with the upper end of t e rod 12 which constitutes one element of the thermostat, it will be evident that the lever 29 which. controls the position, or operation of the circuit controlling tube 17 is under the control of the thermostat. When the thermostat responds to a decrease in temperature, the plunger 40 will, in consequence reciprocate in a direction which causes the lever 29 to swing into the position shown by the full lines in Fig. 3, and this movement of the lever will rock the tube 17 in a direction which will lowerv its electrodes 18 and 19 and cause them to be covered and hence bridged by the body of mercury 20 which flows to the thus lowered end of the tube, the electric heating circuit of the metal pot being thereby closed, and when the thermostat responds to an increase in temperature the plunger 40 reciprocates in the opposite direction and the lever 29 is swung into the reverse position shown by the dotted lines in Fig. 3, and in consequence the tube 17 is rocked into the reverse position shown in'dotted lines in Fig. 3 thus carr ing the body of mercury 20 therein awa rom the electrodes 18 and 19 and the electr1c heating circuit is thereby broken. In Fig. 1, the parts are shown in the positions which they occupy when the thermostat is subject to the influence of a predetermined temperature which is maintained by the flowof gas to the gas burner of the metal pot as permitted by the partially open gas control lever 6, the tube 17 containing the electrodes occupying a position midway between its fully on and fully ofi positions and the electric heating circuit for the metal pot being broken since the electrode 18 is out of contact with the body ofmercury 20. I

When the automatic temperature control device is used in connection with a metal pot which receives its heat from a gas burner alone, the temperature of the metal in the pot will be maintained substantially constant by the gas governor, its valve being automatically opened wider as the temperature of the metal in the pot diminishes and. being moved toward closed position to diminish the supply of gas to the burner when. the temperature of the metal drops, and while the temperature of the metal in the pot remains substantially stationary, the gas control valve of the gas governor will be automatically maintained in a partially opened position where suflicient gas will flow to the burner to maintain such temperature.

When the automatic temperature control device is used with a metal pot which is heated by electric current, the temperature of the molten metal in the pot is automatically maintained substantially constant by the governing of the supply of electric current to the metal pot by the electric controller which is controlled b the thermostat. In this instance, should t e temperature of the molten metal, in the metal pot drop, the thermostat will operate to rock the circuit controlling tube into a position to close the electric heating circuit through the electrodes in .the tube, and should the temperature of the molten metal rise above a predetermined point, the thermostat will operate to rock the circuit controlling tube into a position where the electric heating circuit is broken by the movement of the body of mercury in the tube out of contact with one or both of the electrodes, and by the alternate opening and closing of the electric heating circuit under the control of the thermostat, the temperature of the metal may be maintained substantially constant by the electric heating means for the metal pot.

In using the automatic temperature control device in connection with a metal pot which is heated by both gas' and electric current, the thermostat will act, upon a drop in temperature of the molten metal, to cause increased opening of the gas control valve and rocking of the circuit controlling tube in a direction which will cause closing of its electrodes whereby electric heating current will be supplied to the metal pot, and upon a rise in temperature of the metal above a predetermined point, the thermostat will act to cause movement of the gas control valve toward closed position to reduce the supply of gas to the burner and it will concurrently cause rocking of the electric control tube in a direction to open the electric heating circuit and thereby cut off the supply of electric heating current to the metal pot.. In the particular adjustment of the parts as shown, the gas control valve may normally supply suificient gas to the burner to maintain the molten metal in the metal pot at the predetermined normal temperature and the electric controller will act to close the electric circuit and supply electric heating current which will augment the gas heating uponan abnormal or sudden dro in temperatureof the molten metal, the e ectric heating circuit being open however as soon as the temperature of the molten metal has been restored to normal. The ad'usting screw 8 enables the gas controller to set to operate in a manner to maintain any desired temper- 1 ature of the molten metal, and adjustment of the threaded'rod 34 ofthe electric controller A combined gas governor and electric con troller as hereinbefore described is applicable universally to the metal pots of typographical machines which are heated either by a gas burner or by electrical heating means alone, thus rendering it unnecessary to provide a special temperature control device to be employed in each instance, and it is also applicable to metal pots which are heated both by a gas burner and by electrical heating means, the dual control of both sources of heating energy by the single device and from a single or common thermostat enabling the temperature control device to be applied with facility to the metal pot, notwithstanding the limited space usually available, and when so used, greater uniformity in the temperature of the molten metal is insured since the heating effect of both the gas burner and the electrical heating means will be increased when a sudden reduction in temperature of the molten metal occurs as when fresh metal is added to the metal pot, and the heating effect of both the gas burner and the electrical heating means is reduced or interrupted when the temperature of the molten metal rises.

Furthermore, when both gas and electricity are used as sources of heat energy, the adjusting means hereinbefore described not only enable both of these sources of heat energy to be use-d concurrently but the control means for the electric current supply may be so adjusted that it will normally or whenever desired, interrupt the supply of electric heating current while the gas control means continues to function in a manner to supply gas to maintain the desired temperature of the metalpot, so that while both sources of heat may be used to heat up the metal pot from a cold start, one of the sources of heat energy may be cut off entirely during the operating hours of a day, thus economizing in operating cost.

I claim as my invention 1. An automatic temperature control dea vice for the gas heated or electrically heated metal pot of a typographical machine comprising, in combination a thermostat responsive to the temperature of the metal in the metal pot, a gas governor forgoverning the supply of gas to such metal pot, an electric circuit controller for governing the supply of electric heating current to such metal pot,-

and means for controlling the gas governor and the electric circuit controller from said i thermostat.

2. In a thermostatic control device, the

combination with a gas governor having a between said mem er and said valve for causing operation of the electric circuit controller concurrently with the gas governor, said connection having means for adjusting it to compensate for adjustments of the adjusting means for the valve of the gas governor.

In testimony whereof I have hereunto set my hand.

LE ROY W. WILLIS. 

